Polyamide molding composition containing plagioclase feldspar

ABSTRACT

Filler-containing polyamide mixtures of improved impact strength said fillers being minerals from the feldspar group, and a process for the production of said polyamide mixtures. The content of the filler material is of from 1 to 70 percent, preferably of from 10 to 50 percent, by weight based on the total mixture. Additionally, the mixture can contain an organosilicon compound in an amount of from 0.001 to 1 percent by weight, based on the mineral, of the feldspar group as adhesion promoter.

United States Patent [1 1- Hermann Nov. 20, 1973 POLYAMIDE MOLDING COMPOSITION CONTAINING PLAGIOCLASE FELDSPAR [75] Inventor: Karl Heinz Hermann,

Krefeld-Bockum, Germany [73] Assignee: Bayer Aktiengesellschaft,

Leverkusen, Germany [22] Filed: Mar. 24, 1972 [21] Appl. No.: 237,996

Related US. Application Data [63] Continuation of Ser. No. 8,404, Feb. 3, 1970,

abandoned.

[30] Foreign Application Priority Data Feb. 20, l969 Germany..... P 19 08471.0

[52] US. Cl

3,372,137 4/1968 Tierney 260/37 OTHER PUBLICATIONS Nonmetallic Minerals, Lodoo, 1951 pp. 205-207 USPO Grp. 140.

Cured Rubber and Cpding Ingredients by Pearson, 1918, USPO Library P. 8990 & 99 Condensed Chemical Dictionary 5th Ed., pp. 474-475, 1961.

Primary Examiner-Morris Liebman Assistant ExaminerRichard Zaitlen Attorney-Plumley & Tyner [57] ABSTRACT Filler-containing polyamide mixtures of improved impact strength said fillers being minerals from the feld- V spar group, and a process for the production of said polyamide mixtures. The content of the filler material is of from 1 to 70 percent, preferably of from 10 to 50 percent, by weight based on the total mixture. Additionally, the mixture can contain an organosilicon compound in an amount of from 0.00l to 1 percent by weight, based on the mineral, of the feldspar group as adhesion promoter.

14 Claims, No Drawings 1 POLYAMIDE MOLDING COMPOSITION CONTAINING PLAGIOCLASE FELDSPAR This is a Continuation, of application, Ser. No. 8,404 filed Feb. 3, 1970 now abandoned.

This invention relates to mixtures ofhigh-melting synthetic polyamides with a mineral filler.

It is known that certain mechanical properties of polyamides can be improved by the addition'of inor- I mechanical properties, above all impact strength. In

addition, such fillers as calcium carbonate or glass fibres can only be mixed with a melt of an alreadyprepared polyamide, by means of suitable mixing machines, extruders in particular. They'cannot be added to the polyamide-forming starting materials before polymerisation because calcium carbonate decomposesunder the polymerisation conditions, whilst with glass fibres, technical difficulties are encountered, for example in regard to transportation and homogeneously mixing of polyamide melts containing glass fibres.

It is an object of this invention to provide fillercontaining polyamide mixtures of outstanding impact strength. This object is accomplishedby a composition of matter comprising a polyamide and a mineral from the feldspar group.

Feldspars are anhydrous alkali or lime aluminosilicates, for example orthoclase K [AISi O microcline K [AlSi O anorthoclase (Na, K) [Alsi o land plagioclases, which are preferably used. Plagioclase is the generic name for all triclinic lime-soda feldspars,

that is to say, both the terminal members, albite Na' for example in autoclaves, or continuously, for example lAlSi O and anorthite Ca [Al Si O and also their isomorphous mixtures; for example oligoclase containing from 70 to 90 percent by weight of albite and from 30 to 10 percent by weight of anorthite; andesine containing from 50 to 70 percent by weight of albiteand from 50 to 30 percent by weight of anorthite; labradorite containing from 30 to 50 percent by weight of albite and from 70 to 50 percent by weight of anorthite; or bytownite containing from 10 to 30 percent by weight of albite and from 90 to 70 percent by weight of anorthite (cf. C.W. Correns, Einfuhrung in die Mineralogie, Berlin 1949, page 165 and pages 358 361). Plagioclases have an approximate composition of from 40 to 70 percent by weight of SiO from 15 to 40 percent by weight of M 0 from 0 to 25 percent by weight of CaO, from 0 to 15 percent by weight of Na o and less than 1 percent by weight of Fe O MgO and CO Of the plagioclases, labradorite is preferably used. The feldspar is used in ground form, with an average particle diameter of less than 0.1 mm and preferably less than 0.05 mm.

The filler-containing polyamide mixtures according to the invention can contain from I to 70 percent by weight and preferably from '10 to 50 percent by weight of feldspar, based on the mixture as a whole.

It is another object of this invention to provide a process for the production of filler-containing polyamide mixtures which comprises adding a mineral from the feldspar group to the polyamide material.

Polyamide materials in the context of this invention are polyamides and polyamide. forming starting materials.

The feldspar-containing polyamides show, compared with the unfilled polyamides, a very marked increase in flexural strength and compared with filled polyamides, an increase in impact strength to an extent hitherto unattainable when using any other filler. The, feldspar- :containing polyamide mixtures are best prepared by adding the feldspar to the polyamide-forming starting materials, for example molten caprolactam or an aqueous hexamethylene diammonium adipate solution (AH salt solution) and then carrying out polymerisation or polycondensation in known manner, either in batches,

in VK tubes, optionally in the presence of water or compounds that give off water as catalysts, min the absence of water using alkaline catalysts.

It is also possible, however, homogeneously to mix the feldspar with molten polyamide by means of a suitable mixer, for example an extruder.

In the context of this invention, polyamides include homopolyamides of the kind obtained by the polymerisation or polycondensation of aminocarboxylic acids or their lactams, for example e-aminocaproic acid, llamino 'undecanic acid, 4,4-dimethyl azetidinone, ,B-pyrrolidone, e-caprolactam, enanthic lactam, caprylic lactam or lauric lactam; or by the polycondensa- ,tion of diamines, for example ethylene diamine, hexamethylene diamine, decamethylene diamine, dodecamethylene diamine, 2,2,4- and 2,4,4-trimethyl hexamethylene diamine, pand m-xylylene diamine, bis- (4-aminocyclohexyl)-methane, 3-aminomethyl-3,5,5-

trimethylcyclohexyl amine or 1,4-diaminomethyl cyventional additives such as pigments, dyes, light-, heatand weathering-stabilisers, optical brighteners, plasticisers, crystallisation stimulators, lubricants and release agents and additives for reducing flammability.

Preferably, the filler-containing polyamides also contain, as further additive, from 0.001 to l percent by weight, and preferably from 0.01 to 0.5 percent by weight, based on feldspar, of an organosilicon compound acting as adhesion promoter. Examples of adhesion promoters such as theseinclude vinyl trichlorosilane, vinyl triethoxy silane, vinyl-tris-(B-methoxyethoxy)-silane, vinyl trimethoxy silane, vinyl triacetoxy silane, 'y-methacryloxypropyl trimethoxy silane, N,N-bis- (B-hydroxyethyl)- y-aminopropyl triethoxy silane, 'y-aminopropyl trimethoxy silane, 'y-aminopropyl triethoxy silane, N-B-aminoethyl-y-aminopropyl trimethoxy .silane, B-(3,4-epoxycyclohexyl)-ethyl trimethoxy silane, 'y-glycidyl oxypropyl'trimethoxy silane and mercaptoethyl trimethoxy sila'ne. y-aminopropyl trialkoxy' specimens whose flexural strength is measured in accordance with DIN 53,452 and their impact strength according to DIN 53,45 3.

The data obtained from the various tests and the measurements taken on the test specimens are set out in Table I. r

The following different fillers were used under the same conditions for comparison purposes:

' a. kaolin A having a particle diameter of "less than Primary amino groups, for example B- py fie? 0.04 mm arid an average chemical analysis of 86.4 thoxy silane, may simultaneously be used as chain terpercent by weight of SiO,, 8.5 percent by weight of minators. A1 0 1.8 percent by weight of K,O, 0.7 percent by The filler-containing polyamide mixtures according weight of Fe O 0.2 percent by weight of MgO, 0.'l to the invention are suitable. for the production of percent by weight of TiO 0.1 percent by Weight Of mouldings of all kinds, for example guard-rings for CaO, 0.1 percent by weight of Na,O-and2.1 perfans, housings and parts thereof, screws, gear wheels c nt by weight of heating loss; and components in electrical equipment such as coil b. kaolin B having a particle diameter of less than formers or the bases for keys and contact supports ob- 0.04 mm and an average chemical analysis of 50.3 tained by injection moulding; and bristles, wires, tapes, percent by weight of SiO,, 32.0 percent by weight filaments, sections, plates and tubes obtained by extruof A1 0 1.6 percent by weight of l e- 0 0.8 sion. 1 percent by weight of MgO, 0.6 percent by weight The following examples are to further illustrate the of TiO,, 0.4 percent by weight of (3210, 1.0 percent invention without limiting it. by weight of Na Q, 7.1 percent by weight of heat- EXAMPLE 1 ing residue and 0.5 percent by weight moisture Mixtures of 10 kg of caprolactam and 300 g of s-amicontent; i I I nocaproic acid, with different quantities of labradorite talcum C bavmg a bamcle dlbmeter ofless than powder having a particle diameter of less than 0.03 mm mm n averagfi chemcal analysis of and different quantities of 'y-aminopropyl triethoxy si- 'Percem by weight of Slot Percent by welght lane, are polycondensed in the usual way at a temperaof 3 bbmebt by weight of 0 ture of 270C in an autoclave equipped with stirring berbbnt by welsh of f" percentby weight mechanism. The polyamide melts are then spun into of percent by weight of C301 percent wires approximately 3mm in diameter and chopped by Welght of 2 and Percent by weight of into granulates. The granulates are freed from monotel"; I mcric components by thorough boiling in water, after mica D havmg a Partlcle dlametbr of hi h h are d i d less than 0.03 mm and an average chemical analy- The following characteristics are determined for the sis of Percent y weight of Slot, P products thus obtained by weight of A1 0 10.7 percent by we1ght of K 0 1. The relative viscosity ofa 1 percent by weight solu- L Percent y weight of 9- Percent y tion in m-cresol at 25C in an Ubbelohde viscosimeter, Welght of 2 5, Percent by weigh of 8 and allowance being made for the filler content by suitably 136173611t y 8 of Water; increasing the quantity weighed in. e. Hornblende Asbestos E having a particle diameter 2. The ash content by burning a sample in an open por-' ofless than 0.05 mm and an average chemical analcelain crucible and then calcining the combustion resiysis of 42.2 percent by weight of 810,, 10.3 percent due at 700 to 800C, the increase in weight ofthe cruby weightof AI2O 23.8 percent by weight of cible measured after cooling representing the ash con- MgO, 2.3 percent by weight of Fe O 8.4 percent tent of the sample. by weight of FeO, 0.2 percent by weight of TiOg, The products are then processed ina conventional 5.6 percent by weight of C80, 0.4 percent by screw injection moulding machine into standard test v veight of CO; and 6.8 percent by weight of water.

TABLE 1 'y-Aminopropyl- Impact triethoxy sllane Ash Flexural strength content, strength cm. Percent percent kg./cm kpJemfl, by by Relative DIN DIN N0. Filler Kg. G. weight' weight, viscosity 53452 53453 1 Labradorite 4.0 4.0 0.1 20.2 5.11 1,005 1 5.0 7.5 0.15 34.4 2.00 1,540 0.0 0.0 0.1 30.0 3.05 1,032 4 8.0 8.0 0.1 45.4 5.15 1,500 73.0 4.0 4.0 0.1 20.0 3.15 1,325 54.0 5.0 7.5 0.15 54.0 2.90 1,454 52.4 5.0 5.0 0.1 33.8 2.714 1, 441 22.0 7.0 7.0 0.1 41.7 2.08 1,510 51.0 (0).... Muscovite mica D 4.0 4.0 0.1 29.6 2.86 1,427 28.0 (f)- Hornblcnde-asbestos E" 4.0 4.0 0.1 28.4 2.54 1,349 28.9

1 Based on the Iillor.

-' Based on the polyamide/filler mixture.

3 Did not break.

EXAMPLE 2 kg samples of a colourless polycaprolactam prepared in the usual way with a relative viscosity of 3.12

4. The composition according to claim 1, wherein the plagioclase feldspar is labradorite.

5. A composition of matter accordingto claim 1, comprisinga polyamide, a mineral from the plagioclase e u ed on a 1 percent by weight solution in m- 5 feldspar group and additionally an organosilicon comcresol at 25C in an Ubbelohde viscosimeter) are fused ound as adhe ion promoter, 7

in a conventional extruder and at the same time homo- 6. The composition according to claim 5, wherein the geneously mixed with different quantities of the labracontent of said organosilicon compound is of from dorite powder referred to in Example 1 and different 0.001 to l percentby .weight based on said mineral quantities of 'y-aminopropyl triethoxy silane. The re- 10 from the plagioclase feldspar group.

sulting filler-containing polycaprolactam samples are 7. The composition according to claim 5, wherein the spun into wires approximately 3 mm in diame er, content of the organosilicon compound is of from 0.01

chopped into granulates and dried. to 0.5 percent by weight based on said mineral from the The relative viscosity and ash content of the products plasioclase feldspar group. thus obtained are measured as described in Example 1. 8. The composition according to claim 5, wherein in addition, the products are injection moulded into said organosilicon compound isa'y-aminopropyl trialkstandard test specimens, again as described in Example oxy silane.

l, and their flexural strengths and impact strengths are 9. The composition according to claim- 1, whereinv measured. said polyamide is polycaprolactamf The results of the various tests and the measurements 10. The composition of matter of claim 1 in which taken on the test specimens are set out in Table [1. said polyamide is polycaprolactam, said plagioclase The following different fillers were used under the feldspar is labradorite having aparticle size of less than same conditions for comparison purposes: i 0.05 mni., labradorite comprising 1 percent to 70 pera. kaolinA, as in Example 1 cent by weight of the composition said composition b. talcum C, as in Example 1- also containing 0.01 to 0.5.percent by weight based on c.. dolomite D, with a particle diameter of less than the labradorite of -y-aminopropyl triethoxy silane.

0.03 mm containing approximately 99.5 percent by 11. A process for the production 'of filler-containing weight of CaMg (C09 i polyamide mixtures which comprises adding to polyd. glass fibres E, withadiameter of approximately amide material l to 70 percent by weight based on the 0.01 mm and an average fibre length of approxitotal composition of a mineral from the plagioclase mately 0.3 mm feldspar group having an average particle diameter of e. Muscovite mica D, as in Example 1. less than 0.1 mm."

TABLE I1 v-aiuiuopropyltrlothoxy silane Ash Flexurul content, strength, impact Percent percent kg./cm.-, strength, y b Relative DI em. No. Filler Kg U. weight weight 2 viscosity 53452 kpJcm.

l. Luhrutlorite 2.5 2.5 0.1 20.8 3.08 1,319 4.0 4.0 0.1 23.0 3.10 1,303 0.0 0.0 0.15 37.0 3.07 1,410 70.2 4.0 4.0 0.1 20.2 3.05 1,210 28.2 4 .0 4 .0 0 .1 28.3 3 .07 1, 277 30 .5 00...... 4.0 4.0 0.1 15.2 2.80 300 53.7 1) Glass 001-0 4.0 4.0 0.1 20.0 3.00 1,865 32.1 (e). Museovite mica l)... 4.0 6.0 0.15 27.6 2.94 1,398 26.0

1 Based on the filler.

Based on the polymuide/iilleimixture.

3 Did not break.

What we claim is: I 12. The process according to claim 11, wherein said A composition of matter comprising a resinous o l ide m t rial is a ly-amide 'nelt. polyamide and from 1 to 70 percent by weight based On 13, The process according to claim 11, wherein said the total composition of a mineral from the plagioclase l mide material is a melt of polyamide-forming feldspar group having an average particle diameter of starting material and polymerising the mixture thus obless than 0.1 mm. tained.

2. The composition according to claim 1, wherein 14. The process according to claim 11, wherein an said mineral from the plagioclase feldspar group has an org noilic n compound is added as adhesion proaverage particle diameter of less than 0.05 mm. moter to said mineral from the plagioclase feldspar 3. The composition according to claim 1, wherein the group before said mineral is added to the polyamide' content of said mineral from the plagioclase feldspar material. group is of from 10 to 50 percent by weight based on the total composition. 

2. The composition according to claim 1, wherein said mineral from the plagioclase feldspar group has an average particle diameter of less than 0.05 mm.
 3. The composition according to claim 1, wherein the content of said mineral from the plagioclase feldspar group is of from 10 to 50 percent by weight based on the total composition.
 4. The composition accorDing to claim 1, wherein the plagioclase feldspar is labradorite.
 5. A composition of matter according to claim 1, comprising a polyamide, a mineral from the plagioclase feldspar group and additionally an organosilicon compound as adhesion promoter.
 6. The composition according to claim 5, wherein the content of said organosilicon compound is of from 0.001 to 1 percent by weight based on said mineral from the plagioclase feldspar group.
 7. The composition according to claim 5, wherein the content of the organosilicon compound is of from 0.01 to 0.5 percent by weight based on said mineral from the plasioclase feldspar group.
 8. The composition according to claim 5, wherein said organosilicon compound is a gamma -aminopropyl trialkoxy silane.
 9. The composition according to claim 1, wherein said polyamide is polycaprolactam.
 10. The composition of matter of claim 1 in which said polyamide is polycaprolactam, said plagioclase feldspar is labradorite having a particle size of less than 0.05 mm., labradorite comprising 1 percent to 70 percent by weight of the composition said composition also containing 0.01 to 0.5 percent by weight based on the labradorite of gamma -aminopropyl triethoxy silane.
 11. A process for the production of filler-containing polyamide mixtures which comprises adding to polyamide material 1 to 70 percent by weight based on the total composition of a mineral from the plagioclase feldspar group having an average particle diameter of less than 0.1 mm.
 12. The process according to claim 11, wherein said polyamide material is a polyamide melt.
 13. The process according to claim 11, wherein said polyamide material is a melt of polyamide-forming starting material and polymerising the mixture thus obtained.
 14. The process according to claim 11, wherein an organo-silicon compound is added as adhesion promoter to said mineral from the plagioclase feldspar group before said mineral is added to the polyamide material. 